John R Shapley

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Iodinated X-ray contrast media (ICM) are detected in natural waters at high concentrations relative to other pharmaceuticals due to extensive use in medical diagnostics and high recalcitrance during conventional wastewater treatment. This study examines, for the first time, reductive treatment of ICM in water with hydrogen gas in combination with supported(More)
Catalytic reduction of water contaminants using palladium (Pd)-based catalysts and hydrogen gas as a reductant has been extensively studied at the bench-scale, but due to technical challenges it has only been limitedly applied at the field-scale. To motivate research that can overcome these technical challenges, this review critically analyzes the published(More)
There is considerable need for the rapid destruction of N-nitrosodimethylamine (NDMA) in water because current alternative treatment methods are relatively inefficient. Powdered metal catalysts in conjunction with hydrogen gas showed notable potential for rapid destruction of N-nitrosodimethylamine (NDMA) in water. Palladium, copper-enhanced palladium, and(More)
Catalytic nitrate reduction was evaluated for the purpose of drinking water treatment. Common anions present in natural waters and humic acid were evaluated for their effects on NO3(-) hydrogenation over a bimetallic supported catalyst (Pd-Cu/gamma-Al2O3). Groundwater samples, with and without powder activated carbon (PAC) pretreatment, were also evaluated.(More)
Azo dyes are widespread pollutants and potential cocontaminants for nitrate; we evaluated their effect on catalytic reduction of a suite of oxyanions, diatrizoate, and N-nitrosodimethylamine (NDMA). The azo dye methyl orange significantly enhanced (less than or equal to a factor of 5.24) the catalytic reduction kinetics of nitrate, nitrite, bromate,(More)
The molecular Re(V) complex, chlorobis(2-(2'-hydroxyphenyl)-2-oxazoline)-oxorhenium(V), Re(O)(hoz)(2)Cl, has been investigated as a suitable precursor, when combined with activated carbon powder containing 5 wt % Pd, to provide a heterogeneous catalyst for the reduction of aqueous perchlorate by hydrogen. Two general methods for catalyst preparation have(More)
A new heterogeneous catalyst that promotes the reduction by hydrogen of perchlorate ion in water under mild conditions has been developed. The catalyst is prepared by adsorption of a rhenium(VII) precursor (either ammonium perrhenate or methylrhenium trioxide) onto carbon powder containing 5% palladium by weight. Under standard batch conditions of room(More)
Pd-based catalyst treatment represents an emerging technology that shows promise to remove nitrate and nitrite from drinking water. In this work we use vapor-grown carbon nanofiber (CNF) supports in order to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over(More)
There is a need for new technologies to rapidly and economically treatwater contaminated with N-nitrosodimethylamine (NDMA) and related compounds because of their high toxicity and recent detection in drinking water sources as a consequence of industrial releases and chlorine disinfection of wastewater effluent Treatment of N-nitrosamines with H2 in(More)